In recent years there has been a tremendous increase in the rate of automobile thefts and vandalism and theft from automobiles throughout the nation. Many different types of automobiles anti-theft systems have been designed and marketed. Early systems utilized a unique key-operated switch located on the vehicle's exterior to arm and disarm the system. These keyswitch controlled systems had many shortcomings, including the fact that the connecting wires of the key-switch itself could be bypassed by anyone with knowledge of the automobile system. In addition, the key could be stolen or easily duplicated and used by the thief himself.
Later systems sought to remedy the shortcomings of the earlier key-switch systems, by eliminating the key-switch itself. These "keyless" systems utilized various means to control arming and disarming, including switches hidden from plain view within the passenger compartment, the vehicle's own ignition switch, and digital keypads. However, these "keyless" systems also suffered from a significant shortcoming: if a door to the passenger compartment were opened, the alarm would only sound after an entry delay time, so as to allow the owner enough time to enter the passenger compartment and disarm the system. During this delay time, a thief could steal the stereo unit or other contents of the automobile, and furthermore damage the automobile or even defeat the alarm system, and steal the automobile.
Most recent systems attempt to remedy the entry delay shortcoming by employing remote control techniques. The vehicle owner utilizes a small transmitter to disarm the system from outside of the vehicle prior to entry. However, even these systems suffer the disadvantage of the earliest key-switch types: a lost or stolen transmitter could be used by the thief himself.